diff-bundle does not support cross-model relations

[Andrea Ieri]

On a model that contains cross-model relations:

$ juju export-bundle > /tmp/exported-bundle.yaml
$ juju diff-bundle --debug /tmp/exported-bundle.yaml
22:04:02 INFO juju.cmd supercommand.go:57 running juju [2.6.8 gc go1.10.4]
22:04:02 DEBUG juju.cmd supercommand.go:58 args: []string{"/snap/juju/8873/bin/juju", "diff-bundle", "--debug", "/tmp/exported-bundle.yaml"}
22:04:02 INFO juju.juju api.go:67 connecting to API addresses: [<REDACTED>]
22:04:02 DEBUG juju.api apiclient.go:1092 successfully dialed "wss://<REDACTED>/api"
22:04:02 INFO juju.api apiclient.go:624 connection established to "wss://<REDACTED>/api"
22:04:02 INFO juju.juju api.go:303 API endpoints changed from [<REDACTED>] to [<REDACTED>]
22:04:02 DEBUG juju.api monitor.go:35 RPC connection died
ERROR the provided bundle has the following errors:
relation ["nagios:monitors" "nrpe-controller:monitors"] refers to application "nrpe-controller" not defined in this bundle
relation ["prometheus:target" "telegraf-controller:prometheus-client"] refers to application "telegraf-controller" not defined in this bundle
relation ["graylog:beats" "filebeat-controller:logstash"] refers to application "filebeat-controller" not defined in this bundle
relation ["landscape-server:registration" "landscape-client-controller:registration"] refers to application "landscape-client-controller" not defined in this bundle
22:04:02 DEBUG cmd supercommand.go:496 error stack:
/build/juju/parts/juju/go/src/github.com/juju/juju/cmd/juju/application/bundle.go:104: the provided bundle has the following errors:
relation ["nagios:monitors" "nrpe-controller:monitors"] refers to application "nrpe-controller" not defined in this bundle
relation ["prometheus:target" "telegraf-controller:prometheus-client"] refers to application "telegraf-controller" not defined in this bundle
relation ["graylog:beats" "filebeat-controller:logstash"] refers to application "filebeat-controller" not defined in this bundle
relation ["landscape-server:registration" "landscape-client-controller:registration"] refers to application "landscape-client-controller" not defined in this bundle
/build/juju/parts/juju/go/src/github.com/juju/juju/cmd/juju/application/bundlediff.go:130:

If I manually remove the cross-model relations from the exported bundle, the diff completes successfully.

[Richard Harding (rharding)]

This is supported in 2.7 with the cross model relation support added to the bundles syntax and commands.